Habitat Management Plan Phoenix Park 2008

Phoenix Park Habitat Management
Plan

Report commissioned by The Office of Public Works

Mary Tubridy and Associates Clontarf, Dublin 3
August 2008
Tel 01-8333195

Phoenix Park Habitat Management Plan

Contents

Acknowledgements Summary
34
1 Methodology

1.1 Habitat map

5

1.2 Management plan

2 Habitats

2. 1 Introduction

6

2.2 Wetland habitats
2.2.1 Flora
88

9

2.2.2 Biodiversity evaluation

2. 3 Grasslands
2.3.1 Flora 2.3.2 Biodiversity evaluation
2.4 Woodlands
910 11 11 11 12
2.4.1 Flora 2.4.2 Biodiversity evaluation

3 Habitat Management Plan
3.1 Objectives 3.2 Short to medium term actions
13 13 13 14 14 15 15 16
3.2.1 Habitat and species diversity 3.2.2 Grassland management 3.2.3 Woodland management 3.2.4 Wetland management 3.2.5 Mammals and birds 3.2.6 Research, monitoring and education

References Appendix 1
17

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Notes on habitat diversity in Dublin

Mary Tubridy and Associates

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Acknowledgements

The study benefited from practical assistance, information and advice from the following organizations and individuals:

OPW staff involved in the management of the Phoenix Park, particularly Dr John McCullen Margaret Gormley and Gabriel Gleeson.

Managers of enclosures (Áras, United States Ambassador’s Residence, Zoo). Drs Linda Patton and Maurice Eakin of the National Parks and Wildlife Service

The researchers who carried out specialist studies. They include Tom Hayden and his students from UCD (fallow deer, grey squirrel and mammals); Joe Caffrey and John Coyne of the Central Fisheries Board (freshwater habitats); Olivia Crowe and colleagues in BirdWatch Ireland (birds), Paul Scott of ScottCawley Ltd (bats) and Robbie Meehan (geodiversity).

The public who contributed comments on biodiversity at workshops and through written submissions.

Heritage and Biodiversity Officers of Dublin City Council. Thanks are due to my fellow members of the Conservation Management Advisory Committee.

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Summary

This report provides an account of habitats and recommendations for management to retain and enhance their plant and animal diversity. It is based on fieldwork, a review of specialist reports prepared by other ecologists and discussions between the ecologists who carried out research to inform the Conservation Management Plan.

Habitat mapping confirmed the importance of the Park to biodiversity in Dublin City. Buildings and roads cover 45% of Dublin City. In the park they cover 7%. Woodlands and tree dominated areas cover 30% or 220ha and grasslands cover 56% or 398ha. There are twenty five different habitats including six types of woodland, five types of grassland, as well as hedgerows, scrub, ponds, stream and wet ditches. Semi-natural Dry calcareous and neutral grassland (GS1) is the commonest habitat (29%) followed by

Scattered Trees and Parkland (16%) and (Mixed) Broadleaved Woodland (14%).

Almost all the semi-natural grassland in Dublin is found in the Phoenix Park. The park provides the only location for semi natural Oak-ash-hazel Woodland in the city and throughout the remainder of the wooded areas native Oak (Quercus robur) is the commonest tree. The most valuable habitats are seminatural wet and dry grasslands and woodland. Three legally protected plants have been found within these habitats. The high cover of semi-natural habitats accounts for the wide diversity of animal species found in the Park’ s grasslands, woodlands and wetlands. This biodiversity results from its continuous management over hundreds of years for farming, forestry, deer keeping and amenity. Management recommendations for habitats recognise the importance of its landscape heritage and amenity values. The plan lists thirty-four actions to implement the following overall objectives:

To continue to adopt management measures sensitive to biodiversity, to identify areas where such measures would have precedence and to develop action plans to maximise biodiversity in these area.

To raise awareness of biodiversity and produce guidelines on biodiversity management in co-operation with all stakeholders, institutions and residents.

To protect and enhance the condition of rare and important species of flora and fauna.

To continue research and development and monitoring on all aspects of biodiversity, in order to support the decision making process in management practices for the overall enhancement of biodiversity.

Actions are grouped under the following themes: Habitat and species diversity, woodland, grassland and wetland management, mammals and birds and research, monitoring and education

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1 Methodology 1.1 Habitat map

Habitats were mapped during the summer of 2007 using the classification system and mapping guidelines promoted by the Heritage Council (Fossitt, 2000 and Habitat Mapping Guidelines 2005). Detailed plant lists were compiled at fifty-seven locations. A digital habitat map was produced to which these species lists were linked. A sub-category of Wet Grassland (as GS4*) was mapped to identify the most species rich examples of this habitat. The habitat category Ornamental/non-native shrub (WS3) was mapped both by area and as a linear feature. A map of habitats is an important aid to describing and evaluating biodiversity in the park. Rare habitats can be identified. The results of surveys of specialist groups can be linked to particular habitats and thus management guidelines to enhance both plant and animal biodiversity can target locations known to both managers and ecologists.

1.2 Management plan

Management plan objectives were based on an examination of the results of all field studies commissioned by the OPW, consultations and desk research. Surveys include Crowe (2008), Naulty et al. (2007), Caffrey et al. (2008), Meehan, (2007) and ScottCawley (2007).

The results of the consultation process organised by the OPW (workshops for the public, invitation to make written submissions) were reviewed for references to biodiversity. Discussion of biodiversity related issues at meetings of the Conservation Management Plan Advisory Committee were informed by briefing papers, maps and presentations.

Two research theses which focused on the Park provided valuable background information (McCullen, 2006 and Byrne, 1996) the former because of its focus on landscape history and the latter for its account of grasslands in the park. The results of a soils mapping project (Collins, 1974) were incorporated into the geodiversity assessment (Meehan, 2007).The

publication Wild Plants of the Phoenix Park (Reilly et al, 1993) based on

recording by botanists associated with the Dublin Naturalists Field Club provides a historical review of botanical recording, checklists of flowering plants, bryophytes and trees and notes on the flora associated with different parts of the Park. This publication listed 345 flowering plant species. A survey of semi-natural grasslands in Dublin City (Lyons and Tubridy, 2007) enabled some of the Parks grassland to be evaluated in a city context.

Direct consultations took place with officials from National Parks and Wildlife Service during a site visit. All ecologists involved in field studies in the park, park managers, and an official from NPWS took part in a facilitated workshop to discuss priorities for management. A copy of the habitat map, an account of habitats and list of issues were circulated prior to the workshop.

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2 Habitats

2.1 Introduction

Table 1 describes the relative the cover of (non linear) habitats in the park. Habitat names and codes follow Fossitt (2000).

Table 1

Habitat Areas

Habitat Code and Title

Hectares

Percentage

Area

GS1 Dry

Calcareous and Neutral Grassland

GA2

Amenity Grassland

WD5

206.48

29.42

144.71 112.68
20.62 16.06

Scattered Trees and Parkland

WD1

96.18

54.48 42.85
13.71 7.76 6.11

(Mixed) Broadleaved Woodland

BL3

Buildings and Artificial Surfaces GS4 Wet Grassland WS1 Scrub FL8 Other Artificial Lakes and Ponds

9.18 7.06
1.31 1.01

WS2

6.47

0.92

Immature Woodland

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Table 1 (contd). Habitat Areas

Habitat Code and Hectares Title
Percentage Area

WD3 (Mixed) Conifer Woodland WD2 Mixed Broadleaved/Conifer Woodland

5.75

0.82

3.64

0.52

0.37

GA1 Improved Agricultural

2.60

Grasslands BC4 Flower Beds and Borders WS3 Ornamental/ Non-native Shrub ED2 Spoil and Bare 1.02 Ground WN2 Oak-ash- hazel Woodland GS4* Wet

2.31 1.61
0.33 0.23 0.15 0.15 0.19
1.02 1.34

Grassland (high quality) ED3 Recolonising Bare Ground GM1 Marsh

0.89 0.68
0.13 0.10 0.08

GS2 Dry Meadows 0.59 and Grassy Verges WD4 Conifer

0.24

0.03

Woodland

Linear habitats also shown on the habitat map include Hedgerows (WL1),

Treelines (WL2), Drainage Ditches (FW4), Stone Walls (BL1), Earth Banks (BL2) and linear Shrubberies (WS3).

Twenty five different habitats are found. Semi-natural habitats dominate.

Semi-natural Dry calcareous and neutral grassland (GS1) is the commonest habitat (29%) followed by Scattered Trees and Parkland (16%) and (Mixed)

Broadleaved Woodland (14%). A comparison between the nature and distribution of habitats in the Park and Dublin City (Appendix 1) reveals the significance of the Park to biodiversity in Dublin. Almost all the semi-natural grassland in Dublin is found in the Phoenix Park. The park provides the only location for semi natural Oak-ash-hazel Woodland in the city.

Important features of habitat biodiversity are: 1 Species rich grassland (GS1) along steep terraces on the south side of the park, the flora which includes Hairy Violet (Viola hirta), a protected species. The most valuable grasslands are those which has not been ploughed or improved.

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2 Wet grassland, particularly the wettest area south of the Quarry (or Island) Lake where the flora contains another protected plant, the grass Meadow

barley (Hordeum secalinum). Wet grassland is rare in Dublin.

3 Small area of semi-natural oak ash woodland (0.5ha) dominated by Ash near the Furry Glen.

4 The presence of a type of planted broadleaved woodland (WD1) which has been categorised as “wood pasture” in the United Kingdom. This has not been characterised in Ireland. It is recognized in the UK as a priority habitat (wapis.org.uk). Its principal characteristics are the absence of a shrub layer and abundance of woodland grass species due to grazing pressure.

5 The presence of all other semi-natural habitats is important in the park, as they are rare in Dublin. These include all the other remaining wetlands, other woodlands

Fieldwork confirmed the presence of the legally protected Hairy Violet (Viola hirta) mentioned in Reilly et al. (1993), Hairy St John’s-wort (Hypericum hirsutum) last seen in the 18^thcentury (Reilly op. cit.) and revealed the presence of the legally protected Meadow Barley (Hordeum secalinum) for the first time. These plants are listed in the Flora (Protection) Order 1999 made under the Wildlife Act 1976 (S.I. No. 94 of 1999).

2.2 Wetland habitats

2.2.1 Flora

Wetlands in the park include artificial lakes, streams, drainage ditches and a small area of marsh.

All the lakes in the Park are artificial creations. They include the Furry Glen or Glen pond, Quarry or Island Lake, Citadel or Dog Pond, the Machine pond, the Peoples Garden pond, ponds in the Zoo and a small lake in the grounds of Arus an Uachtaráin. Emergent species found generally in these water bodies include Gipsywort (Lycopus arvensis), Reed Canary-grass

(Phalaris arundinacea), Water Forget-me-not (Mysotis scorpioides), Water Mint (Mentha aquatica), Wild Angelica (Angelica sylvestris), Meadow-sweet (Filipendula ulmaria), Great Willow-herb (Epilobium hirsutum) and Wild Iris

(Iris pseudacorus). Uncommon species include Bulrush (Typha latifolia) at the Citadel or Dog Pond, Mare’s-tail (Hippuris vulgaris) and Water Plantain (Alisma plantago-aquatica) in the lake at Arus an Uachtaráin while Amphibious Bistort (Persicaria amphibia) occurs at both localities. Few non-native invasives are present. The Furry Glen pond has a number of uncommon aquatic species including Reed Sweet-grass (Glyceria maxima) and Yellow Water Lily (Nuphar lutea) the latter also occurring at Quarry Lake. The presence of Chara sp in four ponds (Aras, People’s Garden, Dog and Island) is in indicator of good water quality. No submerged flowering plants were recorded in the lower ponds in the Zoo.

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Because of the heavy drift which comprises a large part of the northern area of the Phoenix Park an extensive drainage system was laid out in the park in the early to mid 19^thcentury (McCullen, 2007). This comprises a system of underground drains and some artificial surface streams . As a result the area of wetland declined. However linear wetlands have continued to survive in many man made or modified locations. The “ha-ha’s” around the Ordnance Survey, Visitor Centre, Aras, Civil Defence grounds and US US Ambassador’s residence support water all year round.The beds and sloping clayey sides of these channels provide valuable niche habitats for a variety of wetland plants. Common plants include Fool’s-water-cress (Apium

nodiflorum), Curled Dock, (Rumex crispus), Common Water-cress (Rorippa nasturtium-aquaticum), Knotted Figwort (Scrophularia nodosa), Hemp Agrimony (Agrimonia eupatoria), Common Fleabane (Pulicaria dysenterica), Brooklime (Veronica beccabunga), Wild Angelica (Angelica sylvestris), Hairy

Sedge (Carex hirta), Remote Sedge (Carex remota), Floating Sweet-grass (Glyceria fluitans) and Plicate Sweet-grass (Glyceria notata). Where water levels are relatively high throughout the year as, for example in the open ditch draining Quarry Lake, additional species such as Water Plantain (Alisma

plantago-aquatica), Branched Bur-reed (Sparganium erectum ), Pink Waterspeedwell (Veronica catenata), Common Spike-rush (Eleocharis palustris), Wild Iris (Iris pseudacorus) and Common Duckweed (Lemna minor) are found.

On the northern shore of the Furry Glen pond marsh has developed on silt while in the valley to the south by the outflow stream, a similar habitat is found on wet impermeable clay sheltered between heavily wooded slopes. On the northern shore of the Furry Glen pond there is an extensive willow scrub mainly comprising Grey Willow (Salix cinerea ssp oleofolia), with

Meadowsweet (Filipendula ulmaria), Wild Iris (Iris pseudacorus), Water Mint (Mentha aquatica), Bittersweet (Solanum dulcamara), Gypsywort (Lycopus europaeus), Marsh Bedstraw (Galium palustre), Wild Angelica (Angelica sylvestris), Water Forget-me-not (Mysotis scorpioides), Fool’s Water-cress (Apium nodiflorum), Greater Willowherb (Epilobium hirsutum) Hedge

Woundwort (Stachys sylvatica) and the characteristic wetland grass species, Creeping Bent (Agrostis stolonifera). South of the Furry Glen pond in the marsh/wet grassland is found a flora dominated by Wild Iris (Iris

pseudacorus), Meadowsweet (Filipendula ulmaria), Wild Angelica (Angelica sylvestris), Common Nettle (Urtica dioica), Hemp Agrimony (Agrimonia eupatoria), Dog-rose (Rosa canina) and Bramble (Rubus spp). Other species include Water Mint (Mentha aquatica), Spear Thistle (Cirsium vulgare),

Creeping Thistle (Cirsium arvense), Lesser Burdock (Arctium minus), Colt’s-foot

(Tussilago farfara) and the introduced Butterfly-bush (Buddleja davidii).

2.2.2 Biodiversity evaluation

The lakes, drainage ditches and streams within the Park provide habitats for a range of plant species, exclusively associated with permanently wet areas. These habitats are rare in Dublin. Of particular value are lakes with varying water depths and unshaded species rich fringing vegetation at their margins.

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2.3 Grasslands

2.3.1 Flora

The influence of topography, soil type, historical drainage works, past management for farming, and current amenity land management accounts for the presence of five types of grassland. The commonest type is Dry calcareous and neutral grassland (Fossit GS1). Best examples are on the drier southern slopes of the Park. Typical grass species in this area are Meadow Oat-grass

(Helictotrichon pubescens), Crested Dog’s-tail (Cynosurus cristatus), Velvet Bent (Agrostis canina), Yellow Oat-grass (Trisetum flavescens), Quaking-grass (Briza media), Red Fescue (Festuca rubra) Heath-grass (Danthonia decumbens) and the

aggressive species Upright Brome (Bromopsis erecta). Other flowering plants

include Spring-sedge (Carex caryophyllea), Crow Garlic (Allium vineale), Lady’s Bedstraw (Galium verum), Salad Burnet (Sanguisorba minor), Wild Thyme (Thymus polytrichus), Fairy Flax (Linum catharticum) and Common Bird’s-foot-

trefoil (Lotus corniculatus). Species richness and rarity at this site in comparison to other sites for GS1 in Dublin was highlighted in Lyons and Tubridy (2007).

A legally protected plant, Hairy Violet (Viola hirta), was refound in this habitat at three locations on steep banks between the Furry Glen and the Magazine Fort. Hairy Violet is rare in Ireland being confined to very restricted areas in the Burren, the Aran Islands, Co. Limerick and Co. Dublin. It is associated with well drained tall old calcareous grasslands. Another rare plant, the Autumn Lady’s-tresses Orchid (Spiranthes spiralis), though not legally protected, was formerly recorded as in this habitat on a dry bank on the south side of the Hurling and Football Grounds. Despite extensive searches over two years it was not refound.

Wet grasslands were identified by the presence of certain grass, rush and sedge species. Wet grassland (GS4) is found not only in depressions but where where drainage systems installed in the 19^thcentury have broken down. Species found in this habitat include Tufted Hair-grass (Deschampsia

cespitosa), Yorkshire Fog (Holcus lanatus), Hard Rush (Juncus inflexus), Soft Rush (Juncus effusus), Compact Rush (Juncus conglomeratus), Oval Sedge (Carex

ovalis), Hairy Sedge (Carex hirta). Other flowering plants include Silverweed

(Potentilla anserina), Lesser Stitchwort (Stellaria graminea), Common Buttercup(Ranunculus acris), Creeping Buttercup (Ranunculus repens) and Cuckoo Flower (Cardamine pratensis). Tormentil (Potentilla erecta) a rare plant

within the Phoenix Park (not recorded by Reilly, 1994) but common elsewhere in similar habitats, was noted in two places in the Park.

During this survey a new Dublin locality for a second legally protected plant, Meadow Barley (Hordeum secalinum), was discovered in this habitat near Quarry Lake. This plant, a species of undisturbed wet grassland has been found in Dublin in recent years only near the coast. It is very rare elsewhere in Ireland.

Despite the absence of farming some grasslands still have the characteristics of Improved Agricultural Grasslands (GA1). In the absence of fertilizer usage